Point-of-Care Testing

In the early days of medicine, few medical tests existed that were done at the patient's bedside. By the 1950s, automated technologies meant centralized clinical laboratories could run large numbers of tests at low cost. It became common to send samples away to laboratories and then wait days to weeks for results.

As the need for faster test results has grown and certain testing devices have become portable and easy to use, medical testing has evolved once again. Today, results from clinical laboratories remain a crucial component of your healthcare, but they are now complemented by tests performed outside of the laboratory, wherever you are.

Point-of-care testing spans so many areas of medicine that it is best defined by where it's done – anywhere outside the centralized laboratory – rather than by the kinds of tests that are performed. It may be referred to by many different names, such as near-patient testing, remote testing, satellite testing, and rapid diagnostics. In general, point-of-care testing encompasses any tests that are performed at or near a patient and at the site where care or treatment is provided. Results are typically available relatively quickly so that they can be acted upon without delay.

Point-of-care tests can happen in a wide variety of locations: in your home, at a healthcare practitioner's office, in the emergency department, in an infectious disease containment unit, in ambulances, at an accident scene, in the military, in the radiology department, on a cruise ship, or even on the space shuttle. And a wide variety of people can perform point-of-care tests, including laboratory professionals, emergency first responders, radiologists, doctors, nurses, physician assistants, or other healthcare practitioners. They may even be done by yourself, sometimes called "self-tests" or "home tests."

Devices for point-of-care tests come in an array of forms. They may use basic dipsticks as with urinalysis, handheld devices like glucose meters, or sophisticated molecular analyzers to detect infectious diseases. A healthcare practitioner may use a handheld device to perform a test at a patient's bedside. Alternatively, that healthcare practitioner may collect a blood sample from the patient and walk the sample down the hallway to a satellite lab, where the sample is processed and tested on instrumentation. Both examples are considered point-of-care testing.

And the same type of point-of-care device may be used by a healthcare practitioner and a "lay person" such as yourself. For example, glucose meters are used by healthcare practitioners in hospitals to monitor patients in intensive care units. Glucose meters can also be used by diabetics at home to monitor levels and to adjust their insulin if necessary. Though the regulation and oversight of the use of these devices may differ when healthcare practitioners use them as opposed to the general public, they are more or less comparable devices.

As healthcare becomes more consumer-focused, the need for convenient diagnosis, monitoring, and screening tests is expanding worldwide. In some cases, technology has caught up; testing devices that are smaller, more portable, and easier to operate have been developed.

The market for point-of-care testing is estimated to grow 9.3% between 2013 and 2018. There are a number of reasons for this trend. Point-of-care tests provide results in real time, rather than in hours or days, so they can help you and your providers make faster, and hopefully better, decisions about your medical care. With results in hand during your consultation, you can receive immediate follow-up testing or treatments without returning for another office visit.

For example, if you are given a point-of-care test and diagnosed with influenza right away, your healthcare practitioner can explain why you don't need antibiotics and instead treat you with an antiviral medication if it's appropriate.

Point-of-care testing is useful as medical care shifts to a focus on prevention, early detection, and managing chronic conditions. In the emergency room, early detection can help determine if people with flu-like symptoms have influenza or if they have a higher-risk infection like Middle Eastern Respiratory Syndrome (MERS). In the healthcare practitioner's office, the rapid strep test allows for earlier treatment of strep throat and reduces the risk of complications from not treating it. At home, glucose meters allow people with diabetes to tailor their insulin therapy. It makes up the largest segment of the point-of-care testing market.

There is also a growing need for rapid screening for infectious diseases like HIV, dengue fever, malaria, and influenza. Infectious disease tests are useful in community clinics and remote or resource-limited areas where there may not be access to a central lab or where infrastructure is limited for transporting samples. Infectious disease tests at the point of care can also lead to prompter treatment, which can prevent infections from spreading.

When time is of the essence, such as in emergency departments or at accident scenes, point-of-care tests provide immediate information about blood gases, electrolytes, or troponin.

When used as part of a larger healthcare strategy, point-of-care testing can make diagnosis and treatment a smoother and more efficient process. Point-of-care tests are most beneficial when they are viewed as one step in a testing continuum that may begin at the point-of-care, but eventually leads to coordinated testing with a central laboratory.

When used properly, point-of-care testing can lead to more efficient, effective medical treatments and improved quality of medical care.

At home, point-of-care tests allow for more frequent and more consistent testing and can empower you to take control of your medical care. Ideally, the end result is higher quality care. For example, clinical trials have shown that individuals monitoring blood thinners (anticoagulants) like warfarin at home had fewer major complications from the treatment.

Point-of-care testing is also crucial in emergency situations and in the operating room. If someone is having a stroke, a first responder or other healthcare practitioner needs to measure prothrombin time/international normalized ratio (PT/INR) to test blood coagulation before he or she can give stroke medications. Point-of-care tests are also used to measure coagulation during open-heart surgery and organ transplants.

Point-of-care tests can also help alleviate emergency room overcrowding by reducing the time it takes to treat people and thus shortening their stays. They are also useful in disaster situations like Hurricane Katrina or any scenario that prevents access to power, water, and laboratory infrastructure.

When used in a healthcare practitioner's office, point-of-care testing can reduce follow-up visits or calls. In one study, delivering the routine tests hemoglobin A1c, hemoglobin, and lipids at the point-of-care decreased tests ordered for each patient by 21%, reduced follow-up calls by 89%, and reduced patient follow-up visits by 61%.

One concern with conventional laboratory testing is that people may not return for treatment if they have to go home and wait for results. This has been the case for HIV viral load and tuberculosis testing. In one study at a clinic in Ghana, point-of-care testing helped remedy this problem. When people seeking care at a tuberculosis clinic were offered HIV tests on the spot, they were more likely to also return for HIV care.

Point-of-care testing can also provide test results in locations where clinical laboratories don't exist or are too far away, like in the developing world, rural regions, or on cruise ships or even the space shuttle.

While many point-of-care tests are designed to be relatively simple and low risk to use, they are not error-proof. Individuals using point-of-care tests, even healthcare practitioners, must carefully follow test directions and be familiar with the test system. Some point of care tests, such as those used to adjust doses of medications, have the potential to lead to serious health consequences if not performed properly. Many large hospitals have point-of-care coordination teams to ensure that testing procedures are properly followed.

It's important that the convenience of point-of-care testing does not tempt users to apply them beyond their intended purpose or misinterpret results. For example, glucose meters and point-of-care hemoglobin A1c tests are designed only for monitoring diabetes and should not be used for diagnosis or screening.

You and your healthcare practitioner also need to be cautious when comparing test results from different sources. Just as test results may not be consistent from laboratory to laboratory, they may vary between point-of-care testing techniques, or between laboratory results and point-of-care results.

One major challenge is managing the data generated by point-of-care tests. When tests are performed at the point-of-care, it is important that the results are incorporated into your health record.

If you are performing point-of-care tests at home, it's best to seek professional guidance. For example, if you are monitoring a medicine like warfarin for anticoagulation, a testing mistake could lead to a blood clot or internal bleeding. That's why it's recommended that you learn to perform the test with professional supervision and have the result verified by a clinician before performing it at home and periodically to ensure consistent technique.

Getting a follow-up diagnosis from a healthcare practitioner is also important if you use home screening tests. For example, the U.S. Food and Drug Administration (FDA) approved HIV testing for home use in 2012. While home tests are less sensitive and home users can make more mistakes than professionals, the FDA thought the benefit of increased HIV testing outweighed the risks.

Home tests and some point-of-care HIV tests used in clinics, for example, detect only HIV antibody and not the HIV antigen, so they may miss some early infections with HIV. All HIV screening tests that are positive should be followed by a second, different antibody test for diagnosis, and should not stand alone to make a diagnosis. Though HIV home tests and point-of-care tests can offer speed, convenience and privacy, it is important for individuals using these tests to seek follow-up care and diagnosis.

While speed is often one of the advantages of point-of-care tests, the results may not be as specific or sensitive as centralized laboratory test results. For example, there are several types of rapid influenza diagnostic tests (RIDTs) available to help differentiate influenza (flu) from other infections with similar symptoms that must be treated differently. Depending on the method, RIDTs may be done in less than 15 minutes in a healthcare practitioner's office or may be sent to a laboratory, with the results available the same day.

But not all RIDTs have the same ability to detect influenza. Some tests can only detect influenza A while others can detect both influenza A and influenza B but not distinguish between the two. Still others can detect and distinguish between influenza A and B but may not detect the latest strain of influenza circulating that year due to antigenic changes in the virus. Moreover, point-of-care flu tests are not designed to identify the subtype of influenza the patient has, i.e. H3N2 or the pandemic H1N1 strain.

Point-of-care tests may also deliver a more limited range of results compared to full laboratory workups. So, following up with a laboratory test will likely be necessary after an initial test at the point of care.

In general, point-of-care tests should be viewed as a valuable tool for medical testing, but not the only tool. Since you benefit most when point-of-care tests and central laboratory tests are coordinated, it's important that point-of-care tests are not used in isolation.

For some conditions, like diabetes, point-of-care testing has already drastically altered how care is delivered and managed. With the market for point-of-care testing only expected to expand, it will continue to change the way healthcare is delivered, making care more patient-driven and focused, providing more data to support evidence-based medicine. Photo source: CDC/Theresa Roebuck

New point-of-care tests that may emerge in the future include new technologies intended to manage critically ill patients in the emergency room, in the hospital, or undergoing surgery, such as complete blood count or tests for drug overdoses. And new tests may be developed for earlier cancer detection, such as cervical cancer. Point-of-care tests will also continue to be important for managing chronic conditions.

Infectious disease testing is the fastest growing area of point-of-care testing. These tests are intended to diagnose infections quickly, to allow timely treatment, limit their spread, and slow or prevent outbreaks. These may include point-of-care tests for Lyme disease, avian influenza (bird flu), chikungunya virus, and drug-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA).

In the developing world and remote rural regions, the use of point-of-care tests is motivated by the need for better options to make diagnosis and treatment of diseases like malaria, HIV, and tuberculosis more accessible and affordable. In the developed world, respiratory and sexually transmitted infections are areas where new point-of-care tests could help.

For the last two decades, efforts have been underway to develop new technologies to bring more tests to the point-of-care and to make the tests more sensitive and specific. Molecular techniques such as polymerase chain reaction (PCR) will likely be used to deliver new infectious disease tests at the point-of-care. Another big focus area has been lab-on-a-chip systems. These miniature devices are designed to rapidly automate every step of a laboratory test using very small sample sizes, without the need for manual handling of the sample.

Point-of-care testing is never likely to replace clinical laboratory testing. However, as technology evolves to meet the demand for more streamlined, higher quality healthcare, point-of-care testing will continue to be a growing part of your healthcare experience.

NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used. To access online sources, copy and paste the URL into your browser.

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